To scan your registry for unecessary/obsolete entried and fix them with CCleaner:
- Click on Registry (left pane)
- This will open up the Registry cleaner menu,select your options
- Click on the "Scan for Issues" button
- The list of obsolete entries will be populated ans once done the "Fix selected issues" button will be available.
- Click on the later and CCleaner will prompt you to make a backup of the registry before proceeding (recommended)
- Click on Yes and follow the procedure